Can't access movie clips

I have created several movie clips in a loop.

for (var i:int=0; i<externalXML.videoClip.length();i++){

 var linkHolder:MovieClip = new MovieClip();
 var linkText:TextField = new TextField();
 linkHolder.ref=i; = "linkHolder"+i;

later i want to go back and alter their appearance. I am having difficulty targetting them:

function clickHandler(event:MouseEvent):void {
 currentVideo =event.currentTarget.ref;
 getChildByName("linkHolder3").x=300; // works fine
 i =3;
getChildByName("linkHolder"+i).x=300;// doesn't work 

How do I target my instanaces please